In some communications systems, e.g., some High Speed Packet Access (HSPA) systems, users may be assigned to use one or more data channels supporting different data rates for uplink communications, e.g., a standard or low rate data channel and, optionally, in addition to the standard data channel, a high speed data channel. In many communications systems, at a given time, a base station will service more users which are assigned the standard or low rate uplink data channel than users assigned both high speed and standard (or low rate) data channels at the same time. However, the number of users being provided high speed data channel service may vary from time to time depending on system loading and user needs.
While processing of standard and high speed data channel signals may involve similar steps such as buffering, filtering, descrambling and despreading, the actual operations may vary depending on whether the signal being processed corresponds to a high speed channel or a standard channel.
FIG. 1 illustrates a known approach for supporting high speed data service. As illustrated in FIG. 1, in order to support high speed service, a standard data channel processing module 110 is provided in addition to a high speed data processing module 112. The standard data channel processing module 110 includes a first number of processing chains for processing standard rate data channels corresponding to different users. As shown in FIG. 1, the antenna 102 may receive uplink signals which are sampled and then processed by the standard data processing module 110 after the samples are buffered, e.g., for 10 ms, by buffer 104. The standard data processing module 110 produces symbols corresponding to one or more user data channels, e.g., for up to the first number of users. In order to support high speed data channels, the samples obtained by sampling the signals received by antenna 102 may also be buffered, e.g., for 2 ms, by buffer 106 and processed by the high speed data channel processing module 112. Note that the buffering for the high speed data channels is by a different amount than for the standard channels, e.g., in accordance with a predetermined standard. The high speed data processing module 112 includes a second number of processing chains, e.g., high speed processing chains, for supporting up to the second number of users as high speed users. The high speed data processing module 112 produces symbols corresponding to one or more high speed user data channels.
The control processor 108 detects control signals received via antenna 102 and controls the standard processing assembly 110 and high speed data processing assembly 112 to process signals corresponding to the users assigned to the high and standard data channels at a given time.
In order to support high data rates a user is normally assigned a high speed data channel in addition to a standard data channel, while when requiring lower data rate service the user is normally assigned the standard rate channel without the benefit of the high data rate channel.
The number of standard data rate channels which can be supported by assembly 110 is normally fixed and intentionally made larger than the number of channels that can be supported by the high speed data processing assembly 112 under the assumption that there will be considerably fewer high speed users than standard rate users at any given time.
The use of processing elements dedicated to standard or high speed data channels may be efficient when a device such as a base station supports a relatively large number of users and the numbers of standard to high data rate users can be expected to be reasonably constant. In small base stations, e.g., small access nodes such as femtocells, very few users may be supported at a given time. In such circumstances, the percentage of users seeking standard data rate service vs high speed service may change dramatically given that there are very few users, e.g., less than 10 users in some cases, being supported at a given time.
In the case of small base stations such as femtocells, implementation cost is often an issue. Accordingly, it is desirable in many cases to minimize the amount of processing circuitry or elements used to implement a small base station such as a femtocell.
In view of the above discussion, it should be appreciated that it would be desirable in at least some base station implementations, if processing resources were not dedicated in a fixed manner to standard or high speed uplink channels but were rather allocatable as needed to either high speed or standard data channel processing. Accordingly, it should be appreciated that there is a need for dynamically allocating processing resources between high speed and standard speed users so that the number of high speed and standard speed users which can be supported can be varied depending on user demands at a given time, e.g., with a larger number of total users and more standard uplink channels being supported at one time and with fewer standard rate uplink users being supported at a second time but with a higher number of high speed users being supported at the second time than the first time.